JP2013531154A - Pneumatic decelerator with constant deceleration capability - Google Patents

Abstract

  The invention relates to a pneumatic reduction device comprising a cylinder and a piston having at least one piston sealing element guided by a piston rod in the cylinder and defining a displacement chamber with respect to the compensation chamber. The speed reducer forms a force against the stroke motion of the piston by the positive pressure in the displacement chamber and the negative pressure in the compensation chamber, and the leakage flow between the displacement chamber and the compensation chamber is at least In the speed reducer affected by the stroke direction, the speed reducer is provided with a closeable air connection at the piston end position of the largest displacement chamber, so that at the end position, the displacement chamber and the compensation chamber are , Communicate with the surroundings. According to the present invention, a pneumatic reduction device having a small variation range of the deceleration force is developed.

Description

  The invention relates to a pneumatic reduction device comprising a cylinder and a piston having at least one piston sealing element guided by a piston rod in the cylinder and defining a displacement chamber with respect to the compensation chamber. The speed reducer forms a force against the stroke motion of the piston by the positive pressure in the displacement chamber and the negative pressure in the compensation chamber, and the leakage flow between the displacement chamber and the compensation chamber is at least The present invention relates to a reduction gear affected by the stroke direction.

  Such a reduction device is known from DE 103 13 659 A1. The force generated during deceleration of a given device may have a large variation when it operates repeatedly.

  Accordingly, an object of the present invention is to develop a pneumatic reduction device having a small variation width of the reduction force.

  This problem is solved by the configuration described in the characterizing part of the independent claims. In order to solve the problem, the speed reducer is provided with an air connection that can be closed at the piston end position of the maximum displacement chamber, so that the displacement chamber and the compensation chamber communicate with the surroundings at this end position. To do.

  Further details of the invention are apparent from the dependent claims and the following description of the schematically illustrated embodiments.

It is a longitudinal cross-sectional view of the speed reducer in a state where the piston rod is pushed in. It is a longitudinal cross-sectional view of the speed reducer in a state where the piston rod is pulled out. It is a partial cross-sectional view of a piston rod and a piston rod seal. FIG. 3 is a detailed view of FIG. 2 in a cylinder top region.

  1 to 4 show the speed reducer (10). The speed reducer (10) is incorporated in a guide system (not shown), for example. This guide system guides and supports, for example, drawers of furniture parts. The guide system includes, for example, a drawing device in addition to the speed reducer (10). For example, when the drawer is pushed in, before the end position is reached, the speed reducer (10) arranged in the drawer engages with an entrainment that is firmly arranged in the furniture part. The stroke movement of the drawer with respect to the furniture part is decelerated. At the same time, or after the drawer has advanced a further partial stroke towards the end position, the withdrawal activates the drawing device. The pulling device pulls the drawer into the closed end position, for example, against the action of the speed reducer (10). At that time, the speed reducer (10) remains engaged with the entrainment body, for example, until the end position is reached. It is also conceivable to use a pneumatic speed reducer (10) without a drawing device.

  The speed reducer (10) includes a cylinder (21), and a piston unit (41) including a piston (51) and a piston rod (42) is guided in the cylinder (21). The piston (51) supports two piston sealing elements (71, 72). For example, the piston rod head (43) of the substantially cylindrical piston rod (42) is configured as a ball head (43) in this embodiment. An entrainment element, a stopper plate, and the like can be connected to the ball head (43).

  The cylinder (21) includes a pot-shaped cylinder jacket (22) having a cylinder bottom (28) incorporated in the cylinder (21) and a top portion (29) closed by a piston rod seal (62). . The cylinder jacket (22) is manufactured, for example, as an injection-molded part made of a thermoplastic, such as polyoxymethylene. In this embodiment, the cylinder jacket (22) is cylindrical on the outside. The length of the cylinder jacket (22) is, for example, 5.5 times the diameter. The non-cylindrical cylinder inner wall (23) is configured in the shape of a truncated cone jacket, for example. The larger cross section of the frustoconical jacket is located at the top portion (29) of the cylinder (21) and the smaller cross section is located at the cylinder bottom (28). The former cross-sectional area is, for example, 63 square millimeters. The gradient of the release cone is, for example, 1:65. The inner wall (23) is optionally polished. The minimum wall thickness of the cylinder jacket (22) is, for example, 7% of its outer diameter.

  The cylinder bottom (28) includes a frustoconical protrusion (31) having a protrusion end face (32) and entering the cylinder inner chamber (25). This protrusion (31), together with the inner wall, defines a ring chamber (33). The cross-sectional area of the ring chamber (33) is 80% of the larger cross-sectional area of the frustoconical jacket. The length of the ring chamber (33) is, for example, 1/7 of the piston stroke. The cylinder (21) may be configured without providing the protrusion (31).

  In the present embodiment, one longitudinal groove (24) is disposed on the cylinder inner wall (23) (see FIG. 4). The length of the longitudinal groove (24) is, for example, 60% of the cylinder length, and ends on the plane of the projecting portion end surface (32) or the cylinder bottom (28), depending on the configuration of the cylinder (21). . The width of the longitudinal groove (24) is, for example, 2% of the larger diameter of the cylinder inner wall (23). In this embodiment, the depth of the groove (24) is 1/4 of the width of the groove (24). The groove (24) has a sharp edge towards the inner wall (23) and the groove outlet has, for example, a 45 ° gradient. Instead of a single groove (24), a plurality of grooves (24) may be arranged on the inner wall (23). The groove (24) may extend along the inner wall (23) of the cylinder jacket (22), for example, spirally.

  The piston rod seal (62) includes an outer support ring (63) and an inner seal lip (64). The piston rod seal (62) forms a piston rod through guide (61). The support ring (63) is in close contact with the piston rod (42). An outwardly facing seal lip (64) surrounds the piston rod (42) and closes the cylinder chamber (25) against the surrounding (1) in the depressed piston position shown in FIG. Seal. The non-tight stopper ring (66) faces the cylinder inner chamber (25).

  The piston (51) and the piston rod (42) of the piston unit (41) are coupled to each other in, for example, a shape connection type and a material connection type (a shape connection type coupling (shape coupling) refers to fitting or meshing) This means a connection based on the geometric relationship between members, and a material connection type bond (material bond) means a bond based on the force of a material (atom, molecule) such as adhesion or welding. The piston (51) and the piston rod (52) may be bonded to each other.

  The total length of the piston unit (41) is, for example, about 5% longer than the length of the cylinder (21). For example, the cross-sectional area of a piston rod (42) manufactured from plastic is, in this embodiment, 1/8 of the inner cross-sectional area of the cylinder (21) at the cylinder top (29). The piston rod (42) may be flexible.

  Both piston sealing elements (71, 72) are arranged between the stopper shoulder (45) of the piston unit (41) and the color disc (56) directed to the displacement chamber (15). The first piston seal element (71) is configured in a pot shape. The first piston seal element (71) is tightly fitted between the piston rod (42) and the piston (51) in the tightening region (73). This tightening region (73) is followed by at least a substantially cylindrical jacket-like sleeve region (74), which forms a deformation region (74). An inwardly extending support ring (75) defines the piston seal element (71) in the longitudinal direction (19). The support ring (75) is guided by a piston notch (52) extending annularly.

  The second sealing element (72) is fitted in the piston notch (52) at a distance from the first sealing element (71) in the representation of FIG. The second sealing element (72) is a shaft seal ring (72) that is open toward the displacement chamber (15) with an outer sealing collar (76). The piston sealing elements (71, 72) are made, for example, from nitrile butadiene rubber having a halogenated surface. Both piston seal elements (71, 72) may be configured as one common component. The total length of the piston seal elements (71, 72) that are spaced apart from each other and are not loaded is hereinafter referred to as the maximum length of the piston seal elements (71, 72).

  The piston (51) is provided with two longitudinal grooves (53) located on the opposite sides in the region of the piston notch (52), and the longitudinal groove (53) is a cutout (57) of the color disk (56). ). These longitudinal grooves (53) connect the pressure chamber (17) of the first piston seal element (71) to the displacement chamber (15).

  The piston rod (42) comprises a plurality of longitudinal passages (48) in a section (46) adjacent to the stopper shoulder (45) on its outer surface (47). For example, the length of the longitudinal passage (48) distributed uniformly along the circumference corresponds to the thickness of the cylinder top seal (62), for example in a direction parallel to the piston rod (42). The length of the at least one longitudinal passage (48) corresponds, for example, to the length of the sealing lip (64) including the non-contact area (65) of the sealing lip (64). Moreover, the longitudinal passage (48) projects beyond the seal lip (64) toward the piston rod head (43). For example, the depth of the longitudinal groove (48) is 3% of the diameter of the piston rod (42), and the width of the longitudinal groove (48) is 16% of the piston rod diameter. Therefore, the total cross-sectional area of the longitudinal passage (48) is 5% of the piston rod cross-sectional area.

  Instead of the longitudinal passage (48) described here, the piston rod (42) may comprise a plurality of passages (48) arranged in a spiral. These passages (48) may extend in the same direction or in opposite directions, and the passages (48) may intersect or penetrate each other.

  In this embodiment, in the longitudinal direction (19) of the speed reducer (10), the distance between the seal lip (64) of the cylinder top seal (62) with respect to the start end portion of the groove (24) provided in the cylinder inner wall (23) is The distance of the start end portion of the longitudinal passage (48) to the end of the seal collar (76) of the second piston seal element (72) on the side of the displacement chamber is 3 millimeters longer. The latter length includes the length of the longitudinal passage (48), the length of the transition region (44) between the longitudinal passage (48) and the piston seal elements (71, 72), and all the piston seal elements (71, 72) and the maximum length.

  After assembly, in this embodiment, the piston (51) and the cylinder bottom (28) define a displacement chamber (15). The piston (51) and the cylinder top (29) define a compensation chamber (16). The piston seal element (71) and the piston (51) define a pressure chamber (17), and the pressure chamber (17) is pushed through the longitudinal groove (53) and the cutout portion (57). Connected to the retreat room (15).

  When the piston (51) of the reduction gear (10) is pulled out (see FIGS. 2 to 4), the piston (51) is located in the region of the larger inner diameter of the cylinder (21). For example, the piston (51) is located in a smooth region (26) of the cylinder inner wall (23) where no groove is provided. The seal collar (76) non-tightly contacts the cylinder inner wall (23). The sleeve region (74) is located between the cylinder inner wall (23) and the piston (51) without deformation with radial play on both sides.

  When the piston (51) is pushed in (see FIG. 1), the piston seal elements (71, 72) contact the cylinder inner wall (23) in a non-tight manner in the region of the longitudinal groove (24). At that time, the longitudinal groove (24) connects the displacement chamber (15) and the compensation chamber (16).

  For example, when the drawer is pulled out after being attached to the furniture part, for example, the speed reducer (10) is not engaged with the entrainment body. The piston unit (51) is in its extended end position as shown in FIGS. At that time, the stopper shoulder (45) may contact the piston rod seal (62). Further, the speed reducer (10) may be configured such that the stopper shoulder (45) is spaced from the piston rod seal (62) by, for example, 2 to 3 millimeters at the end position where the piston unit (41) is pulled out. Good. For this purpose, for example, a mechanical stopper may be arranged on the piston rod (42) outside or inside the cylinder (21).

  For example, when closing the drawer, the entrainment body surrounds the piston rod head (43) or an entraining element arranged on the piston rod head (43) with a partial stroke of the total stroke that contacts the closed end position of the drawer. .

  The piston rod (42) is pushed in under the action of an external force. At that time, the piston (51) is slid toward the cylinder bottom (28) (see FIG. 1) from the cylinder top (29) (see FIGS. 2 to 4). At that time, the volume of the displacement chamber (15) (the displacement chamber (15) has the maximum volume in the display of FIGS. 2 to 4) is reduced. The gas pressure, for example the air pressure in the displacement chamber (15), is increased and acts as an internal force on the piston seal element (71). In accordance with the self-help principle, the seal collar (76) is pressed against the cylinder inner wall (23) while being deformed as the piston rod (42) starts to be pushed. The displacement chamber (15) and the compensation chamber (16) are insulated from each other almost tightly. As soon as the sealing lip (64) reaches the cylindrical section (49) of the piston rod (42), the compensation chamber (16) is tightly sealed against the surroundings (1) by the piston rod seal (62). The When the piston (51) is continuously pushed, a negative pressure is formed in the compensation chamber (16).

  The pressure formed in the displacement chamber (15) also acts on the inner surface of the brake sleeve (71). The sleeve region (74) is curved radially outward and pressed against the inner wall (23).

  When the brake sleeve (71) is deformed, the piston seal element (71) is shortened in the axial direction. The support ring (75) is displaced towards the piston rod (42), e.g. along the frusto-conical piston notch (52), in which case the deformation region (74) is additionally directed radially outwards. In this case, the braking effect of the braking sleeve (71) is strengthened. The connection passages (53, 57) are not interrupted, so that the displacement chamber (15) and the pressure chamber (17) are in communication with each other during the total stroke.

  When the piston rod (42) is continuously pushed in, the seal collar (76) pressed against the cylinder inner wall (23) and the brake sleeve (71) contacting the cylinder inner wall (23) greatly reduce the piston stroke motion. Give rise to The drawer is strongly braked.

  As the stroke of the piston rod (42) increases, the seal collar (76) of the piston seal element (72) reaches the beginning of the longitudinal groove (24). As soon as the seal collar (76) passes the edge of the throttle passage (24) behind it, air is pushed away from the displacement chamber (15) to the compensation chamber (16) via the throttle passage (24). The pressure in the displacement chamber (15) drops rapidly, for example. In so doing, the brake sleeve (71) may still abut against the cylinder inner wall (23). The volume of air displaced from the displacement chamber (15) is larger than the volume of the expansion of the compensation chamber (16) by the piston rod (42) penetrating the compensation chamber (16). The pressure in the compensation chamber (16) is increased. In doing so, air can escape from the compensation chamber (16) to the surroundings (1) through a piston rod seal (62) that seals against the surroundings (1).

  As soon as the piston seal element (71) is completely disengaged from the inner wall (23), additional air immediately flows from the displacement chamber (15) to the compensation chamber (16). The piston seal element (71) again occupies the starting position before the start of the stroke movement. The drawer has a low residual speed at that time. At the end position, the drawer stays unbounced.

  During deceleration of the stroke movement, the drawer can be connected to a drawing device. The retracting device includes, for example, a spring, which exerts an additional internal force on the guide device. This force acts as an external force on the reduction gear (10).

  After a relatively long period of time has elapsed without continuing to operate the speed reducer (10), the pressure in the displacement chamber (15) and the compensation chamber (16) is the same as the ambient pressure. In the stationary position, for example, when material fatigue occurs, there is no concern that the speed reducer (10) may burst due to negative or positive internal pressure.

  When the drawer is withdrawn again, air flows from the compensation chamber (16) to the displacement chamber (15) via the throttle passage (24). The piston seal element (71) remains almost undeformed and does not contact the cylinder inner wall (23) for at least the majority of the stroke. During the withdrawal movement, air flows from the compensation chamber (16) to the displacement chamber (15) with little hindrance, so that the withdrawal movement proceeds at least almost without resistance.

  During the withdrawal of the piston unit (41), the compensation chamber (16) is reduced and the displacement chamber (15) is enlarged. Based on the volume of the piston rod (42), the volume of air displaced is smaller than the volume of the expansion chamber (15). The air pressure in the displacement chamber (15) and the compensation chamber (16) decreases.

  Shortly before the piston unit (41) reaches the extended end position, the displacement chamber (15) has its maximum volume, and the seal lip (64) of the piston rod seal (62) is connected to the piston rod (42). At least one flutes (48) provided on the top are reached. Thereby, the air connection part (18) between a cylinder inner chamber (25) and circumference | surroundings (1) is opened. From the surroundings (1), air flows into the compensation chamber (16) and the displacement chamber (15). The air pressure in these chambers (15, 16) is the same as the ambient pressure.

  As soon as the piston rod (42) is completely pulled out, the entrainment element on the piston rod side is dissociated from the entrainment body on the furniture part side. The speed reducer (10) is disengaged. At that time, the piston rod (42) of the speed reducer (10) has been pulled out. The retractor is dissociated.

  When the piston (51) is pushed in again, the air connection (18) of the cylinder inner chamber (25) with respect to the surrounding (1) is first closed again. The sealing lip (64) reaches the cylindrical area (49) of the piston rod (42). After the piston unit (42) is continuously pushed in, the seal collar (76) of the shaft seal ring (72) reaches the longitudinal groove (24) of the cylinder inner wall (23).

  As a result, ambient pressure acts on the displacement chamber (15) at the start of each deceleration stroke. Thereby, the speed reducer (10) is repeatable and has a constant speed reduction capability.

  Instead of the longitudinal passage (48) provided on the piston rod (42), the elastically deformable piston rod (42) can be bent from its extended position at the extended end position. At that time, since the piston rod seal (62) is deformed and becomes non-tight, air can flow from the surrounding (1) into the compensation chamber (16) and the displacement chamber (15) for pressure compensation. .

  It is also conceivable to open a separate valve at the end position with which the piston unit (41) is withdrawn. This valve may be incorporated into the piston rod seal (62), for example.

  The speed reducer (10) may be configured such that the displacement chamber (15) is disposed between the piston (51) and the piston rod seal (62). The piston rod (42) passes through the displacement chamber (15). The compensation chamber (16) is located between the piston (51) and the cylinder bottom (28).

  In one form of such a reduction gear (10), the deceleration is performed when the piston rod (42) is pulled out. The area | region where the groove | channel is not provided of the cylinder inner wall (23) is in contact with the cylinder bottom. In the present embodiment, the longitudinal passage (48) provided on the piston rod (42) is disposed beside the piston rod head (43), for example. Further, in this embodiment, it is conceivable to deform the piston rod (42) or arrange a valve on the piston rod seal (62), whereby the displacement chamber (15) at the terminal position of the piston unit (41). And the air connection (18) between the surrounding (1).

  The speed reducer (10) described here may be part of a guide system.

DESCRIPTION OF SYMBOLS 1 Perimeter 10 Deceleration device 15 Push-out chamber 16 Compensation chamber 17 Pressure chamber 18 Air connection part 19 Longitudinal direction 21 Cylinder 22 Cylinder jacket 23 Cylinder inner wall 24 Vertical groove, throttle passage 25 Cylinder inner chamber 26 Groove of cylinder wall 23 is provided Unoccupied area 28 Cylinder bottom 29 Head part, Cylinder head 31 Projection part
32 Projection end face 33 Ring chamber 41 Piston unit 42 Piston rod 43 Piston rod head, ball head 44 Transition region,
45 Stopper shoulder 46 Piston rod 42 section 47 Outer surface 48 Vertical passage 49 Cylindrical section of piston rod 42 51 Piston 52 Piston notch 53 Vertical groove 56 Color disc 57 Cutout and connection passage 61 Piston rod through guide 62 Piston Rod seal, cylinder top seal 63 Support ring 64 Seal lip 65 Non-contact area of seal lip 64 66 Stopper ring 71 Piston seal element, first seal element, brake sleeve 72 Piston seal element, second seal element, shaft seal Ring 73 Tightening area 74 Sleeve area, deformation area 75 Support ring 76 Seal lip, seal collar

Claims (7)

A cylinder (21) and at least one piston seal element (71; 72) guided by a piston rod (42) in the cylinder (21), and the displacement chamber (15) into the compensation chamber (16) A pneumatic decelerator (10) comprising a piston (51) defining a
The speed reducer (10) forms a force that opposes the stroke motion of the piston (51) by the positive pressure in the displacement chamber (15) and the negative pressure in the compensation chamber (16), In the speed reducer, the leakage flow between the displacement chamber (15) and the compensation chamber (16) is influenced at least in the stroke direction,
The speed reducer (10) comprises an air connection (18) that can be closed at the piston end position of the largest displacement chamber (15), whereby the displacement chamber (15) and The compensation chamber (16) communicates with the surroundings (1), and is a pneumatic speed reducer.   The speed reducer according to claim 1, wherein the air connection (18) is arranged on a piston rod seal (62) and / or the piston rod (42) surrounding the piston rod (42).   The speed reducer according to claim 2, wherein the piston rod seal (62) comprises a single lip seal (64) directed to the piston rod head (43).   The speed reducer according to claim 1, wherein the air connection (18) is formed by at least one longitudinal passage (48) arranged on the piston rod (42).   The speed reducer according to claim 4, wherein the length of the longitudinal passage (48) is shorter than 5% of the piston stroke.   The cylinder (21) comprises a cylinder inner wall (23) having at least one longitudinal groove (24) oriented in the longitudinal direction (19), the length of the longitudinal groove (24) being the cylinder (21) The piston (51) is located at the maximum end position of the displacement chamber (15) and in a region of the cylinder inner wall (23) where no groove is provided. The speed reducer according to claim 1.   The sum of the length of the longitudinal passage (48), the maximum length of all the piston seal elements (71, 72) and the length of the transition region (44) is provided in the groove of the cylinder inner wall (23). Deceleration according to claim 3, 5 and 6, which is shorter than the distance measured in the longitudinal direction (19) between the end of the displacement area (26) on the side of the displacement chamber and the single lip seal (64). apparatus.

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